xii Proceedings. [Januaiy gtli,igi2. 



The Invasion of Insect Pests. 



Brief reference has been made to the effect which the 

 opening up and settlement of a new country has upon the 

 insect life of that country. Not only is the native insect life 

 affected, but the gates of a promised land are thrown open tO' 

 the alien hordes without, and the history of economic entomology 

 in Canada is a record of successive invasions of injurious 

 insects, or of the first discovery of their previously unnoticed 

 entry. Most of our seriously injurious insects are species which 

 have invaded Canada from without. The Hessian Fly {Mayetiola 

 destr7tctor '$,diy) reached Canada about 1816. A few years later 

 it was followed by another serious pest of Canada's staple crop, 

 namely, the Wheat Midge {Diplosis /nV/V/ Kirby), which crossed 

 the frontier in 1828, and from time to time has been responsible 

 for enormous losses. In 1866 the Chinch Bug {Blissns leucop- 

 tetus Say), which in sixty years has exacted a toll of not less 

 than three hundred and fifty million dollars in the United 

 States, was first found in Ontario. Four years later the Colorado 

 Potato Beetle {Leptifwtarsa decemlineata Say), in devastating, 

 millions, swept across the frontier, and now is the most 

 commonly reported pest in Eastern Canada, and in its spread 

 westward has reached Alberta. 



All these insects confined their ravages to field and cereal 

 crops. In 1882, however, it was discovered that the Farch 

 Sawfly {Lygaeo!ie??iatus erichso?iii Hartig), which had been first 

 observed five years previously in the New England States, had 

 reached Canada. Its depredations were so serious that in a few 

 years the mature larches, or tamaracks, over practically the whole 

 of Eastern Canada, were almost completely destroyed. About 

 1887 the Dominion Entomologist received specimens of the 

 Pear-leaf Blister Mite {Eriophyes pyri Nalepa) from Nova Scotia, 

 which, although it is not an insect in the strict sense, for 

 practical purposes is regarded as such. It was undoubtedly 

 introduced on nursery stock from Europe, and has now spread 



